1. Field of the Invention
The present invention relates to an electrically conductive paste used for electronic elements having external electrodes, such as laminated capacitors, and to an electronic element having electrodes which are formed from the electrically conductive paste. In particular, the present invention relates to an electrically conductive paste predominantly containing Cu and to an electronic element having electrodes which are formed from the conductive paste.
2. Background Art
Conventionally, internal electrodes have been constituted of base metal materials such as Ni or Cu in order to reduce the production cost of laminated ceramic capacitors and other elements. Production of such electronic elements has involved formation of external electrodes by application and firing of an electrically conductive paste mainly comprising inexpensive copper powder. Briefly, outer electrodes are formed by application of an electrically conductive paste comprising Cu powder, zinc borosilicate glass frit, an organic binder resin and a solvent to an outer surface of a ceramic body in which an internal electrode was formed, and firing.
However, an electrically conductive paste applied to an outer surface of a ceramic body having an internal electrode made of a base metal must be fired in a low-oxygen-concentration atmosphere due to susceptibility to oxidation of the base metal such as Ni or Cu. When conventional electrically conductive pastes predominantly containing Cu are fired in a low-oxygen-concentration atmosphere, dense external electrodes might not be formed therefrom due to poor sinterability. Also, conventional electrically conductive pastes employing zinc borosilicate glass frit must be fired in a strictly controlled atmosphere but might not form dense external electrodes even when the atmosphere is strictly controlled.